Method and limitations

MacBlend adapts the chart-matching workflow used by Marco Meyer’s mmColorTarget and Jed Smith’s CalibrateMacbeth.

Before you start

In the Image Editor sidebar, Color Space selects the image input transform, often called an IDT. It turns the file’s stored values into the scene-linear working values required by the calculation. For example, Panasonic V-Log/V-Gamut footage should use the matching Panasonic input transform available in your Blender color configuration.

Find out more about color spaces and transforms in Blender.

The display/view transform changes how the image looks on screen. It does not change the values MacBlend samples. Do not choose Non-Color just to change the preview; use it only when the image data is deliberately meant to bypass color conversion.

When Use reference values as target is enabled, choose the gamut in which the source was recorded. For example, use V-Gamut for a Panasonic V-Gamut image. This tells MacBlend which known chart values to compare against. It does not select a creative look or delivery color space.

What happens when you sample

First, align the four overlay corners with the four corners of the chart. MacBlend then finds the center of every patch and averages a small square of pixels there. Keep that square inside the colored part of a patch, away from borders, glare, shadows, and reflections.

You can either sample a second chart image as the target, useful for matching camera A to camera B, or use MacBlend’s built-in chart references. The built-in references start from D65 values and are converted for the recorded gamut you choose.

What Forward and Inverse mean

Forward moves the sampled source toward the selected target. Inverse moves data from the selected target back toward the sampled source. Both directions are written when you export LUTs.

Normalize handles a broad brightness difference before the color correction is calculated. Create Exposure Node keeps that brightness adjustment visible as its own node after the color transform. Leave it enabled when you want to inspect or adjust that exposure change separately.

What it cannot do

A single color correction cannot fix everything. It will not reliably repair gamma errors, display rendering, clipped highlights, a local grade, a selective hue adjustment, uneven lighting, glare, shadows, or a damaged chart.

Use a clean, evenly lit, properly exposed chart and minimally processed imagery. The built-in chart references assume D65 conditions, so unusual lighting can make a reference-based result less accurate. Always check the transformed chart and representative shot content before relying on the result.

Learn more

These resources continue from approachable introductions through practical guidance to technical background and the original Nuke implementations: